JP2024090396A - Wind turbines and wind power generation equipment - Google Patents

Abstract

[Problem] To provide a windmill and wind power generation device that prevents mechanical damage to the blades, reduces the wind speed required for initial startup, and has excellent startup characteristics. [Solution] A windmill that includes a rotating shaft and a number of blades that are spaced apart at equal intervals on concentric circles centered on the central axis of rotation of the rotating shaft, and that can rotate together with the rotating shaft when wind strikes the blades, and that includes an opening that can eject a jet behind the trailing edge of the blade, and a jet ejection device that controls the ejection of the jet from the opening. [Selected Figure] Figure 4

Description

The present invention relates to wind turbines and wind power generation devices.

Wind turbines that harvest wind energy can be broadly divided into horizontal axis and vertical axis turbines. The horizontal axis turbine is the propeller type, which is the most widely used type worldwide. Although this type of turbine is highly efficient, when the wind direction changes, the direction of the rotation axis must be reoriented in the direction of the wind. On the other hand, vertical axis turbines are effective against winds from any direction, making them suitable for environments where the wind direction changes frequently.
Vertical axis wind turbines are classified into drag type and lift type. A typical drag type is the Savonius wind turbine, which is still widely used today. This type of wind turbine has a large starting torque but generally low efficiency.
On the other hand, Darrieus wind turbines and Gyromill wind turbines are typical lift-type wind turbines. Lift-type wind turbines use the lift acting on the blades when they are rotating, so not only do they have a small starting torque, but they also have low efficiency when rotating at low speeds, specifically when the circumferential speed ratio (circumferential speed of the blades/wind speed) is 1 or less. In particular, Darrieus wind turbines have a low starting torque, so attempts are being made to use them in combination with Savonius wind turbines.
Gyromill wind turbines, also known as linear Darrieus wind turbines, have a relatively high starting torque and are capable of autonomous starting.
However, as a characteristic of the lift type, the torque and efficiency are low at low speeds. However, these types of wind turbines have been attracting attention in recent years due to their excellent characteristics such as low noise and good starting characteristics.
For example, as shown in Patent Document 1, a turbine is known in which auxiliary blades are provided at the rear ends of the blades to reduce the wind speed required for initial startup and increase the drag and lift of the rotor, thereby improving power generation efficiency.

JP 2013-515203 A

However, as the rotational speed of the wind turbine increases, the auxiliary blades may bend outward due to centrifugal force, creating resistance to the flow and causing a sudden drop in torque. In addition, because the auxiliary blades are made of an elastic material, they can be subject to fatigue damage due to repeated deformation and have poor durability in natural environments.
In order to solve the above problems, an object of the present invention is to provide a wind turbine and a wind power generation device that prevent mechanical damage to the blades, reduce the wind speed required for initial start-up, and have excellent starting properties.

The wind turbine configuration for solving the above problems includes a rotating shaft and a number of blades arranged at equal intervals on concentric circles centered on the central axis of the rotating shaft, and the blades are capable of rotating together with the rotating shaft when wind hits them. The wind turbine is configured such that the blades have openings behind their trailing edges through which a jet can be ejected, and the wind turbine is equipped with a jet ejection device for controlling the ejection of the jet from the openings.
According to this configuration, the blades can be rotated by the reaction force of the jet, which helps start the rotation of the wind turbine even when the wind is weak (wind speed is low).
In addition, because the blades have a wing shape, lift is generated by the reaction force of the ejected jet, which can help start the rotation of the wind turbine even when the wind force is weak (wind speed is slow).
Furthermore, since the opening is formed so as to open along the extension direction of the blade, the jet ejected from the opening functions as a flap as known in aircraft, etc., and together with the reaction force of the ejected jet, a large lift force is obtained, thereby assisting in starting the rotation of the wind turbine.
In addition, the jet ejection device ejects jets based on the wind direction relative to each blade, thereby reducing the consumption of energy required for ejecting the jets.
Also, the jet ejection device stops ejecting the jet from the blade facing the headwind,
By ejecting the jet from a blade that is facing the wind, the energy consumption required to eject the jet can be reduced.
The wind power generation device includes the wind turbine according to any one of claims 1 to 4 and a generator that generates power by rotation of the rotating shaft, so that power generation can be started even when the wind speed is slow.

1 is an external view showing a vertical axis wind turbine generator according to an embodiment of the present invention. FIG. 2 is a side cross-sectional view showing a vertical axis wind turbine generator. FIG. 2 is a diagram showing the surface shape of a blade when viewed in cross section along the chord direction. 4 is an enlarged cross-sectional view of a connecting portion between the rotating shaft and the arm and a connecting portion between the arm and the blade. FIG. FIG. 2 is an enlarged plan view of the blade viewed from the trailing edge side. FIG. 2 is a cross-sectional view including an opening provided at the trailing edge of the blade. FIG. 2 is a block diagram of a jet injection device. This is an image of what happens when a jet is ejected from a blade. FIG. 13 is a block diagram showing another embodiment of the jet ejection device.

The present invention will be described in detail below through the embodiments of the invention, but the following embodiments do not limit the invention as claimed, and not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention, but include configurations that are selectively adopted.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
Fig. 1 is a plan view of a vertical axis type wind turbine generator 1 according to an embodiment of the present invention. Fig. 2 is a side cross-sectional view of the wind turbine generator 1.
As shown in Figures 1 and 2, the wind turbine generator 1 includes a rotation mechanism 2 that rotates when it receives wind W, a power generation mechanism 4 that converts mechanical energy obtained by the rotation mechanism 2 into electrical energy, a jet injection device 8, and the like.
The rotating mechanism 2, the power generating mechanism 4 and the jet ejection device 8 are disposed on the upper part of a base 6 which stands on the ground F and extends vertically.

The rotating mechanism 2 includes a wind turbine 10 that receives wind W, a rotating shaft 20 connected to the wind turbine 10, and a casing 40 that supports the rotating shaft 20 rotatably about a central axis C via bearings 30.
The wind turbine 10 according to this embodiment is, for example, a gyromill type wind turbine, which is a type of vertical axis wind turbine. The wind turbine 10 is independent of the wind direction and is configured to be rotatable around the central axis C of the rotation shaft 20 regardless of the wind W from any direction.

The lower end of the casing 40 is fixed to the upper end of the base 6. The casing 40 is formed in a multi-stage cylindrical shape with the upper part 41 (wind turbine 10 side) having a smaller diameter than the lower part 42 (base 6 side).

The lower portion 42 of the casing 40 accommodates, for example, the power generation mechanism 4 and the jet injection device 8 (not shown).
The power generation mechanism 4 includes a generator (not shown) that converts mechanical energy obtained by rotating the rotating shaft 20 in the circumferential direction (around the central axis C) into electrical energy to generate electricity.

The generator is configured, for example, by providing a magnet rotor (not shown) at the lower end of the rotating shaft 20 so that it rotates together with the rotating shaft 20, and disposing a coil stator (not shown) so as to surround the outer periphery of the magnet rotor.

A bearing 30 that rotatably supports the rotating shaft 20 is provided on the inner peripheral surface of the upper part 41 of the casing 40. The outer periphery of the bearing 30 is fitted into the inner peripheral surfaces of the upper and lower ends of the upper part 41 of the casing 40, and the rotating shaft 20 is fitted to the inner periphery.

As shown in Figures 1 and 2, the lower end of the rotating shaft 20 is rotatably supported by bearings 30;30 relative to the casing 40 and extends upward. The rotating shaft 20 supported by the bearings 30;30 has a central axis C perpendicular to the ground F.

One end of an arm 12 for supporting the blade 11 is connected to the outer circumferential surface of the rotating shaft 20. In this embodiment, the arm 12 is described as being connected to the rotating shaft 20 via an intermediate member 15. The intermediate member 15 is provided at two positions above and below the rotating shaft 20, spaced a predetermined distance apart.
In this embodiment, the arm 12 is described as a hollow pipe having a circular cross section, but the cross-sectional shape is not limited to a circle.

A plurality of arms 12 (three in this embodiment) are connected to each intermediate member 15 so as to extend radially outward from the outer circumferential surface of the rotating shaft 20. The arms 12 connected to each intermediate member 15 are arranged at equal intervals around the circumference of the rotating shaft 20. The arms 12 connected to each intermediate member 15 are also arranged so as to line up vertically above and below. Hereinafter, the arms 12;12 lined up vertically above and below are referred to as arm pairs 12;12. In this embodiment, there are three pairs of arm pairs 12;12.

One blade 11 that receives wind W is connected to the other end of the arm pair 12;12 so as to extend vertically to the ground F. In this embodiment, three blades 11 are provided via the arm pair 12;12 at equal intervals in the circumferential direction on a concentric circle about the central axis C of the rotating shaft 20.
Each blade 11 is attached to a pair of arms 12; 12 so that a line segment connecting the leading edge and the trailing edge is tangent to a circle of rotation of the blade 11 when it rotates.

FIG. 3 is a diagram showing the surface shape of a blade when viewed in cross section along the chord direction.
In this embodiment, the blades 11 have a wing shape capable of generating lift when subjected to wind W. That is, the wind turbine 10 is configured to rotate the rotating shaft 20 by the lift generated when the blades 11 receive the wind W.

Here, we will explain the connection structure between the rotating shaft 20 and the arm 12, and the connection structure between the arm 12 and the blade 11. The rotating shaft 20, arm 12, and blade 11 in this embodiment are each configured to be hollow.

FIG. 4 is an enlarged cross-sectional view of a connecting portion between the rotating shaft and the arm and a connecting portion between the arm and the blade.
As shown in FIG. 4A, the rotating shaft 20 and the intermediate member 15 are configured to have through holes 20A and 15A, respectively, through which one end of the arm 12 can enter the hollow portion of the rotating shaft 20.
As shown in FIG. 4B , the blade 11 and the connecting member 25 are configured to have through holes 11A and 25A through which the other end of the arm 12 can enter the hollow portion of the blade 11 .

In the wind turbine 10 of this embodiment, the hollow arm 12 is fixed to the rotating shaft 20 and the blades 11 with both ends open, and the hollow portion of the rotating shaft 20 is connected to the hollow portion of the blades 11 via the arm 12.

Fig. 5 is an enlarged plan view of the blade from the trailing edge side, and Fig. 6 is a cross-sectional view including an opening provided at the trailing edge of the blade.
The blade 11 according to this embodiment is configured to be able to eject a jet J rearward from the trailing edge 13. Note that the jet J refers to, for example, pressurized air ejected as a unidirectional flow.
5 and 6, the blade 11 is configured to have an opening 80. The opening 80 is provided, for example, as a circular hole extending in the chord direction from the center of the blade span at the trailing edge 13. A hole wall 80a defining the opening 80 is formed in the blade 11 as a cylindrical surface extending in the chord direction.

The openings 80 are provided, for example, in all of the blades 11 that make up the wind turbine 10. The size of the openings 80 should be such that the compressed air supplied to the blades 11 can be ejected from the openings 80 as a jet J.

FIG. 7 is a block diagram of a jet injection device.
The jet injection device 8 is configured, for example, to include compressed air generating means 100 that generates compressed air that is the source of the jet J that is ejected from the blade 11, a rotation angle detection means 120 that detects the rotation state of the rotating shaft 20, a wind speed detection means 130 that detects the wind speed of the wind W, and a jet control means 140 that controls the supply of compressed air to the blade 11.

The compressed air generating means 100 can be composed of, for example, a compressor, a regulator, a valve, etc. The compressed air generating means 100 adjusts the compressed air pressurized by the compressor to a predetermined pressure using a regulator, and opens and closes a valve to output or stop the adjusted compressed air. In this embodiment, the valve is described as an electromagnetic valve that opens and closes in response to an electrical signal. The valve is connected to the rotating shaft 20, and is piped so that compressed air can be supplied to the hollow portion of the rotating shaft 20 when the valve is open.

The piping from the valve to the rotating shaft can be, for example, provided with a rotary joint at the opening at the lower end of the rotating shaft 20, and the rotary joint and the valve can be connected with a pipe. By configuring the piping in this way, it is possible to supply compressed air to the hollow part of the rotating shaft 20 while maintaining the rotation of the rotating shaft 20.
The flow path for supplying compressed air from the compressed air generating means 100 to each blade 11 in the rotating shaft 20 is not limited to one using piping, and for example, a flow path instead of piping may be formed by providing a shielding plate (partition wall) in the rotating shaft 20. In other words, it is sufficient that a flow path is formed that can supply compressed air from the compressed air generating means 100 to each blade 11 individually.

The compressed air supplied to the hollow part of the rotating shaft 20 is then supplied to the hollow part of the blade 11 via the hollow part of the arm 12, and is ejected as a jet J from an opening 80 provided at the trailing edge of the blade.

The rotation angle detection means 120 is provided so as to be able to detect the rotation of the rotating shaft 20. The rotation angle detection means 120 can be, for example, a sensor such as a rotary encoder that can electrically output the detected rotation (angle) of the rotating shaft 20.

The wind speed detection means 130 can utilize a sensor configured to detect the speed (wind speed) of the wind W around the wind turbine 10 and output the detected wind speed as an electrical signal.

The jet control means 140 can be configured by a so-called computer or the like. The computer referred to here is, for example, a device equipped with hardware such as a CPU as a processing means and ROM, RAM, etc. as storage means, and can be of any form, such as a PLC (Programmable Logic Controller).

The jet control means 140 is electrically connected to the valve, the rotation angle detection means 120, the wind speed detection means 130, etc., and can be configured to calculate the rotation speed of the rotating shaft 20 based on the change in the rotation angle of the rotating shaft 20 detected by the rotation angle detection means 120, and control the opening and closing of the valve based on the calculated rotation speed, or control the opening and closing of the valve based on the wind speed detected by the wind speed detection means 130.

The jet control means 140 can be configured, for example, not to output a signal to the valve when the wind speed is lower than a preset threshold value or when the rotational speed of the rotating shaft 20 reaches zero or a predetermined number of rotations.
This makes it possible to reduce energy consumption when the wind speed is too high to rotate the wind turbine 10 or when sufficient wind speed is obtained to cause the jet J to reach an unnecessary rotation speed.

The jet control means 140 can be configured to output a signal to the valve, for example, when the wind speed reaches a preset threshold. The threshold here means the wind speed at which the jet J can be ejected to start the wind turbine 10.

FIG. 8 is an image diagram of when a jet J is ejected from the blade 11. As shown in FIG.
As shown in FIG. 8 , the wind turbine 10 can generate a rotational force on the rotation shaft 20 around the central axis C of the rotation shaft 20 by ejecting a jet J from each blade 11 regardless of the direction of the wind W.
Therefore, when the wind speed of the wind W is slightly insufficient to start the wind turbine 10, the jet J is ejected, so that the wind turbine 10 can start rotating.
In addition, when the wind W exceeds the amount of rotational force that can be obtained, the jet J is stopped from being ejected, thereby preventing unnecessary consumption of energy.

In the above embodiment, the jet control means 140 has been described as spraying or stopping the jet J based on the wind speed of the wind W and the rotation speed of the rotating shaft 20, but the present invention is not limited to this.
For example, the jet control means 140 may eject the jet J from each blade 11 based on the wind direction relative to the blade 11 .

When using blades 11 that generate lift by receiving wind W, as in the wind turbine 10 described in this embodiment, it is known that, of the three rotating blades 11, the blades 11 facing the wind direction (wind W is a headwind) generate lift, but the blades 11 facing the wind direction as a tailwind do not generate lift. In other words, it can be said that the blades 11 facing the wind direction as a headwind have a greater force for rotating the rotating shaft 20 by the amount of lift than the blades 11 facing the wind direction as a tailwind.

Therefore, the jet ejection device 8 may be configured to stop ejection of the jet J from the blades 11 facing the wind direction, and eject the jet J only from the blades 11 facing the wind direction. In other words, the jet ejection device 8 is controlled so that ejection and ejection are repeatedly stopped while one blade 11 rotates once around the rotation shaft 20.
By configuring the jet injection device 8 in this manner, the energy required to generate the jet J can be reduced.

FIG. 9 is a diagram showing another embodiment of the jet ejection device.
In this case, as shown in FIG. 9, the jet injection device 8 may be configured to include a wind direction detection means 160 in addition to the compressed air generation means 100, rotation angle detection means 120, wind speed detection means 130, and jet control means 140 described above.
The wind direction detection means 160 may be, for example, a sensor configured to be able to output the detected direction of the wind W as an electrical signal.

The wind direction detection means 160 will be described as outputting the direction of the wind W based on, for example, the installed direction (an azimuth angle of 0° (180°) set in the sensor itself).
The wind direction detection means 160 may be provided, for example, such that the position of an azimuth angle of 0° coincides with the position of 0° of the rotation angle detection means 120. This allows the position of one blade 11 to coincide with 0° of the rotation angle detection means 120 and with an azimuth angle of 0° of the wind direction detection means 160, making it easy to identify the positions of the other two blades 11 relative to the direction of the wind W (wind direction).

In this case, it is also necessary to supply compressed air to each blade 11. Therefore, for example, electrically opened and closed valves can be provided at the ends of all arms 12 that enter the hollow portion of the rotating shaft 20, and each valve can be connected to the jet control means 140 by wiring. The wiring connecting the valves and the jet control means 140 can be extended, for example, downward through the hollow portion of the rotating shaft 20, and connected from the hollow portion of the rotating shaft 20 to the jet control means 140 outside the rotating shaft 20 while maintaining an electrical connection via a slip ring or the like within the upper part 41 of the casing 40.

Therefore, the jet control means 140 can output a signal to the valve of the arm pair 12;12 connected to the blade 11 that has reached the wind direction among the rotating blades 11, thereby causing the jet J to be ejected from that blade 11. In addition, the jet control means 140 can stop outputting a signal to the valve when that blade 11 has rotated 180°.

By controlling the ejection of jet J in this way, it is possible to assist and stabilize the rotation of the wind turbine 10 when necessary.

The ejection of the jet J from the blade 11 is not limited to the above control and may be changed as appropriate. However, it is preferable to control the ejection of the jet J so as to reduce the consumption of energy required for ejection of the jet J while increasing the power generation efficiency of the wind turbine generator 1.

In addition, in the above embodiment, one opening 80 is provided as a circular hole extending in the blade span direction from the center on the trailing edge 13 at the center position of the blade span of each blade 11, but this is not limited to this. In other words, the number of openings 80 is not limited to one, and multiple openings may be provided in the extension direction of the trailing edge 13.

Although the opening 80 has been described as being provided as a circular hole, its shape is not limited. For example, the opening 80 may be a slit extending along the trailing edge 13 of the blade 11. By configuring the opening 80 in this manner, the jet J ejected from the opening 80 functions as a flap, and the lift acting on the blade 11 can be increased.

Although the opening 80 has been described as being provided on the trailing edge 13, this is not limited thereto, and it may be provided on the wing member forming the inner wing surface, the wing member forming the outer wing surface, or a combination of these. The key to forming the opening 80 is that the jet J is ejected behind the blade 11.

The size and shape of the opening 80 should be such that the compressed air supplied to the blade 11 can be ejected as a jet J.

In addition, in the above embodiment, the jet J is described as being sprayed or stopped based on the wind speed of the wind W, the rotation speed of the rotating shaft 20, the wind direction, etc., but the spraying or stopping of the jet J may be controlled by combining, for example, the wind speed of the wind W, the rotation speed of the rotating shaft 20, the wind direction, etc.

In addition, the control over the ejection and stopping of the jet J is not limited to the configuration described in the above embodiment, but may be appropriately configured depending on control factors such as the wind speed of the wind W, the rotation speed of the rotating shaft 20, and the wind direction for controlling the ejection of the jet J.

As described above, by providing the wind turbine 10 with the opening 80 capable of ejecting the jet J behind the trailing edge 13 of the blade 11 and by providing a jet ejection device that controls the ejection of the jet J from the opening 80, it is possible to rotate the blade 11 by the reaction force of the jet J. For example, even when the wind force is weak (wind speed is slow), it is possible to assist in starting the rotation of the wind turbine 10.
Furthermore, because the blades 11 have a wing shape, lift is generated by the reaction force of the ejected jet J, which can assist in starting the rotation of the wind turbine 10 even when the wind force is weak (wind speed is slow).
Furthermore, by forming the opening 80 so as to open along the extension direction of the blade 11, the jet J ejected from the opening 80 functions as a flap as known in aircraft, etc., and together with the reaction force of the ejected jet J, a large lift force is obtained, which helps start the rotation of the wind turbine.
In addition, the jet ejection device stops ejecting the jet J from the blade 11 facing the wind,
By ejecting the jet J from the blade 11 with a tailwind, the consumption of energy required to eject the jet J can be reduced.
Furthermore, by including the wind turbine 10, the wind power generation device can generate power even when the wind speed is slow.

In this embodiment, the invention is applied to a gyromill (H-rotor) type wind power generation device that rotates around a vertical axis, but it can also be applied to various types of wind power generation devices, such as a helical H-rotor type, Darrieus type, cross-flow type, and Savonius type.

In the above embodiment, the wind turbine 10 is described as rotating using wind W as the working fluid, but the wind turbine 10 may also be used as a water turbine (impeller) that uses water as the working fluid.
That is, the application of the wind turbine 10 is not limited to wind power generation equipment, and the same effects can be obtained even if the wind turbine 10 is used in a hydroelectric power generation equipment.

1 Wind power generation device, 8 Jet injection device, 10 Windmill, 11 Blade,
12 arm, 13 rear edge, 20 rotation axis, 80 opening,
100 compressed air generating means, 120 rotation angle detecting means, 130 wind speed detecting means,
140 jet control means, 160 wind direction detection means, C central axis, J jet, W wind.

Claims (6)

A windmill comprising a rotating shaft and a plurality of blades arranged at equal intervals on a concentric circle centered on a central axis of rotation of the rotating shaft, the plurality of blades being rotatable together with the rotating shaft when wind strikes the plurality of blades,
the blade has an opening through which a jet can be ejected behind a trailing edge of the blade;
A wind turbine comprising a jet injection device for controlling the injection of a jet from the opening. The wind turbine according to claim 1, characterized in that the blades have an airfoil shape. The wind turbine according to claim 1 or 2, characterized in that the opening is formed so as to open along the extension direction of the blades. The jet injection device is
2. The wind turbine of claim 1, wherein the jets are directed based on the wind direction relative to each blade. The jet injection device is
The jets from the blades that are facing the wind are stopped,
2. The wind turbine according to claim 1, wherein the jet is ejected from a blade facing a tailwind. The wind turbine according to any one of claims 1 to 5 is provided.
A wind power generation device equipped with a generator that generates electricity by rotation of the rotating shaft.

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